Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge in the field.
EEG waveforms are routinely recorded in clinical settings for the diagnosis of epilepsy and other conditions that are evident in brain wave data. These EEG waveforms are typically measured using an array of sensors applied to a headpiece secured to the head by a straps extending from the headpiece and fastened under the chin.
The application of these sensors typically requires parting the hair and the removal of any dead scalp tissue by applying a conductive abrasive gel. The sensors are coupled to the headpiece, typically though use of a clip or screw, such that when the headpiece is used, it applies a positive pressure to the sensor toward the scalp. This method of arranging the sensors typically allows continuous EEG measurement for about an hour before the scalp preparation must be reapplied.
An alternative solution, e.g. as proposed by Advanced Brain Monitoring Inc, provides a wireless sensor headset which can be worn for about eight hours of continuous use. However, for this device to provide a connection between the sensors and the scalp for eight hours, the sensor excretes a conductive cream through the hair during use. The current art typically teaches methods of improving and maintaining a stable conductive connection between the sensor and the scalp to overcome this problem.
There is a need in the art for a method and apparatus of measuring scalp potential that is less demanding on its requirement for conductivity to the scalp.